Thank you for that link.
I guess my main concern is verification of the CMU board in pack 3 and finding a couple of used cells for replacement of the low voltage one.
I have bought a broken 2010 IMIEV. Found a problem with the obc and did this repair. then cleared all fault codes. Now left with these 3 fault codes
P1A33 - cell voltage sensor (BMU)
P1A39 - charge state signal error (BMU)
U1924 - Bat -Lin bit error
Looking like a fault in CMU board...